EachTectical intetspace f epreseots one degree Fahrenheit, and the fractional parts of a degree are indicated as exactly as possible in the plotting of the curves. Each fifdi 

 dcOTsee JS represented by a slightly lieayjer line. The transverse interspaces inclosed by die heavier lines represent periods of ten days each, as indicated by the dates on the 

 left-hand side of die plate, The lighter traitsverse lines, intermediate between die heavier ones, are intended to represent die mean of each ten days, and the curves of temper- 

 Bttn'e are plotted with reference fo these lines. The left-hand vertical division is devoted to the air temperatures for i83i, 18S2 and 18S3, the middle division, to i the surface 

 water temperatures for the samayearS',thuspermittiDg of acompadson of die two; and the dgjithand divLsiaa to liie v^ater temperatures for 1884 and 1885. 



